1. Field of the Invention
The present invention relates to a spray gun for spraying paints and similar viscous media that can be propelled pneumatically or electrically, comprising a gun housing for accommodating the propulsion mechanism, components of the spray gun that effect mixture and/or metering, a handle projecting from the gun housing, and a reservoir tank removably attached to the gun housing for holding the medium to be processed, as well as a union nut placed on the gun housing or an intermediate piece connected to the gun housing or an extension pipe, and an air cap surrounded by the union nut provided with mutually offset outlet openings for compressed air by means of which various spray jets can be formed and with an atomiser nozzle assigned to it that is held in an oriented position and can be opened by means of a nozzle needle.
2. Description of the Prior Art
Spray guns of this type have been offered for sale for many years by J. Wagner GmbH, Markdorf under the name W 850 E and have proven their effectiveness in practice. By turning the air cap through 90° in this case, it is possible to set three jet shapes for performing different jobs, namely a horizontally oriented flat jet, a round jet and a vertically oriented flat jet.
In order to set one of these spray shapes with this spray gun of the prior art, it is necessary to unscrew the union nut and turn the air cap to the corresponding position by hand with the union nut loosened. Then the union nut needs to be tightened again. However, the air cap has to be held in place when doing this in order to prevent it turning inadvertently. Also, the air cap can only be aligned precisely by visual contact, particularly when setting a round jet in order to cover the air supply to the outlet openings. Quite apart from the significant amount of time required in order to make these adjustments and settings, it is also necessary for the operator who is using the spray gun to use both hands in order to perform this task. Since it is necessary to use one hand to grip the air cap that has paint residue on it, the unavoidable consequence of changing the spray shape is that the operator will get his or her hands dirty. In many cases, therefore, the operator prefers not to change the spray shape in order to avoid getting paint on his or her hands.
The purpose of the present invention is therefore to create a spray gun of the aforementioned type that enables the shape of the spray jet to be changed within a short time without the need to grip the air cap and therefore without the need to put up with getting dirty hands. Rather, it should be possible to change the spray shape merely by turning the union nut or an equivalent holding element. The constructional complexity required in order to achieve this should be kept at a low level whilst nevertheless always allowing a reliable setting to be achieved quickly and in a straightforward procedure.